This invention relates to the integration of the wireless and wireline networks and, in particular, to the integrated wireless/wireline registration that facilitates the routing of PCS calls to a landline device.
Telephones are linked through telecommunication systems that include the public switched telephone network (PSTN), which is continually being improved through such developments as the Advanced Intelligent Network (AIN). Devices that are linked through the PSTN with the aid of the AIN include conventional telephones, radio telephones (often referred to as cordless phones), answering machines, facsimile (fax) machines, computers, and computer peripherals such as modems, printers and the like. These devices in most cases are physically linked to the PSTN through copper wire and in some cases fiber optic lines. Thus, these devices are referred to herein as xe2x80x9cwirelinexe2x80x9d or xe2x80x9clandlinexe2x80x9d devices. A telecommunications system such as the PSTN that serves wireline devices is referred to herein as a xe2x80x9cwirelinexe2x80x9d or xe2x80x9clandlinexe2x80x9d network.
A wireline device, as its name implies, keeps its user tied to a particular geographic location through a line connected to a wireline network. For example, a wireline device in a person""s home or office may be used only in the limited area of that home or office. Based on this tie to particular geographic location, a subscriber""s directory number in the wireline network generally is associated with the particular geographic location of the wireline devices used by the subscriber.
To break this tie to a particular geographic location, wireless telecommunications devices for use in wireless networks have been developed. A wireless telecommunications device is also referred to herein as a xe2x80x9cwireless unitxe2x80x9d or a xe2x80x9cmobile unitxe2x80x9d. The most familiar wireless units are cellular phones, which are also referred to as mobile phones and, when used in a car, as car phones. But wireless units may include other communication devices that operate on principles of radio or microwave technology. The most familiar types of wireless networks include the cellular mobile radio telephone (CMR) system and the personal communication network (PCN).
A wireless unit does not fetter its user with ties to a particular geographic location. Rather, a wireless unit may be used anywhere within a geographic area served by the subscriber""s wireless network or by another wireless network through arrangements for such service made with the subscriber""s wireless network. Based on the mobile nature of a wireless unit, a call to a subscriber using a wireless unit is directed to a number that is associated with the wireless unit. In the CMR system, this number is often referred to as a subscriber""s xe2x80x9ccell phone numberxe2x80x9d or xe2x80x9cmobile phone number.xe2x80x9d
Given the convenience of wireless units, their popularity is growing. But it is not yet an exclusively wireless world. For various reasons, including those of cost, infrastructure, and special services, a user may be a subscriber of both a landline service and a wireless service. For example, a salesperson may use a landline device in his or her home or office and may use a wireless unit in his or her car. In many cases, a subscriber""s landline service is completely separate from the subscriber""s wireless service. Where these services are separate, to reach a particular subscriber, a caller may have to call both the subscriber""s landline directory number, which is associated with a particular geographic location, and the number which is associated with the subscriber""s mobile unit. Trying to reach a subscriber by making two calls to two different numbers is inconvenient and inefficient. It is also inconvenient and inefficient to burden the subscriber with having to distribute more than one number to potential callers. It is further inconvenient and inefficient to burden a potential caller with having to know both of the numbers associated with the subscriber.
To overcome the problems associated with a subscriber having to use a landline device with a landline number and a wireless unit with a wireless number, some subscribers have made use of call forwarding services offered by the service providers of the landline service or the wireless service. For example, a subscriber may implement a call forwarding service with respect to his or her wireless number so that, for a time, all calls directed to the wireless number are forwarded to the landline number. A disadvantage of such an implementation of the call forwarding service is demonstrated in the case of a caller making a call from a wireless unit to the subscriber""s landline number. The call is routed from the wireless network in which the caller""s wireless unit is operating to the landline network in which the subscriber""s landline device is located. But as noted, the subscriber""s landline number has a call forwarding service implemented on it so that calls are forwarded to the subscriber""s wireless unit. So, in this example, the call from the caller using the wireless unit is routed back from the landline network in which the subscriber""s landline device is located to the wireless network in which the subscriber""s wireless unit is located. This back-and-forth routing of a call from a first network to a second network and then back to the first network is known as xe2x80x9ctromboningxe2x80x9d or the xe2x80x9ctromboning effectxe2x80x9d.
FIG. 1 illustrates a case of tromboning with respect to a call that is routed from the landline network 12 to the wireless network 14 and back to the landline network 12. In this second example, assume a subscriber has implemented the call forwarding service on his or her wireless number associated with wireless unit 28d so that all calls to the wireless number are forwarded to the subscriber""s landline number (associated with landline unit 16d). Also assume that a caller uses his or her landline device 16a to dial a call to the subscriber""s wireless number. The call originates in the landline network 12 and is routed from the caller""s landline unit 16a as indicated by arrow A through the service switching point (SSP) 18a and as indicated by arrow B to access tandem 20. From the access tandem 20, the call is routed to the wireless network 14, and in particular, through the access tandem 20 as indicated by arrow C to the mobile telephone switching office (MTSO) 22 serving the wireless number.
As a result of the implementation of the call forwarding service on the wireless number, a check of the home location register (HLR) 24, as indicated by arrows D and E, results in forwarding of the call from the subscriber""s wireless number to the subscriber""s landline number. Thus, the call is routed from MTSO 22 as indicated by arrow F through access tandem 20 and back to the landline network 12. In particular, from access tandem 20, as indicated by arrow G, the call is routed to the SSP 18b which serves the subscriber""s landline number. From the SSP 18b, as indicated by arrow H, the call is terminated to the wireline device 16d associated with the subscriber""s landline number. Thus, the call suffers from the tromboning effect by being routed: (1) from the landline network 12 to the wireless network 14 as indicated by arrows A, B, and C; and (2) back from the wireless network 14 to the landline network 12 as indicated by arrows D, E, F, G, and H.
In this example, tromboning occurs with respect to this call for the following reasons: (1) the call originates in a first network; (2) the information with respect to the call forwarding service is located in a second network; and (3) the call forwarding information indicates that the call is to be routed back to the first network. In other words, the call has to cross from the first to the second network so as to obtain the information that the call must double back to the first network.
The tromboning of a call adversely impacts the call because the back-and-forth routing of the call from one network to another and back to the first network results in a delay in the processing of the call. In addition, the tromboning of a call has negative consequences on the networks that are involved in the back-and-forth routing of the call, because the tromboning detrimentally occupies network resources that otherwise could be used to handle other traffic.
The tromboning effect and its problems have been described in the context of back-and-forth routing between a landline network and a wireless network that results from the implementation of a call forwarding service. But the tromboning effect may occur between any two communication networks where a call or other communication originates with a first network, is routed to a second network, and then is re-routed for termination or connection to a unit operating in the first network.
Accordingly, there is a need for a method and system that overcomes the problems associated with a telecommunications subscriber having to keep track of two different numbers and possibly having to dial two different numbers (a landline number and a wireless number) to reach a subscriber who utilizes both landline service and wireless services.
There is also a need for a method and system that prevents the tromboning effect with respect to the routing of a call or other communication from a first device to a second device.
There further is a need for a method and system that prevents the tromboning effect with respect to the routing of a call or other communication between two communication networks wherein a call or other communication originates with a first network, is routed to a second network, and then is re-routed for termination or connection to a device operating in the first network.
The present invention addresses the above described needs by providing a system and method for routing telephone calls directed to a wireless unit located in a wireless network to a landline device located in a landline network. The present invention utilizes a location register in the form of a service control point (SCP) located in the landline network to store certain information pertaining to landline numbers and respective routing numbers associated with landline devices. Functionally coupled to the SCP is a Visitors"" Location Register (VLR). The VLR facilitates the receiving of subscriber information from the wireless network relating to subscriber identity and verification as well as the features and services to which the subscriber has subscribed. Additionally, the SCP is also functionally coupled to a landline network element that facilitates the routing of communications both to landline devices and over to the wireless network. In general, the landline network element is in the form of an Access Tandem (AT). In routing the communications to the landline devices, the communications are transmitted from the landline network element to the landline devices via Switch Servicing Points (SSP), of which each are individually capable of accessing numerous landline devices.
As the primary link between the landline network and the wireless network, the landline network element is functionally coupled to a Mobile Telephone Switching Office (MTSO) located in the wireless network. The MTSO houses the field monitoring and relay stations for switching calls between the wireless network and the landline network. Associated with the MTSO is a Home Location Register (HLR) that facilitates the storing of certain subscriber information used to identify and to verify a subscriber, as well as containing information on the features and services the to which subscriber subscribes. The MTSO completes the connections to the wireless units via individual cell sites positioned in various areas to provide coverage over a defined geographic area. The cell sites then transmit the calls to the wireless units in accordance with instructions received from the MTSO.
In particular, the routing of telephone calls, initially directed to a wireless unit located in the wireless network, to a landline device located in the landline network is primarily accomplished by registering the wireless unit with the landline network. The registering is accomplished by dialing an administrative number from the landline device where the subscriber wants their wireless calls to be directed. Once the administrative number is received by the AT in the landline network, a query is made by the AT into the SCP and associated VLR to see if the subscriber is identified and verified. If so, the wireline registration feature is set to the xe2x80x9conxe2x80x9d state in the VLR in the landline network. Once set to the xe2x80x9conxe2x80x9d state, the information is subsequently transmitted to the HLR in the wireless network. Upon receipt, the information within the HLR is updated to instruct that all calls directed to the subscriber""s wireless number are to be directed to the landline number of the landline device from which the subscriber registered. The information transmitted to the HLR in the wireless network is transmitted directly from the SCP and associated VLR located in the landline network. Hence, the VLR in the landline network directly communicates with the HLR in the wireless network to keep both the landline and the wireless networks up to date as to the registration status and specific routing for the various subscribers.
By providing the capability for the VLR in the landline network to directly communicate with the HLR in the wireless network, both networks will be able to route the calls efficiently and alleviate the tromboning effect that often occurs when calls are redirected from a wireless unit to a landline device.
Accordingly, an object of the present invention is to provide a method and system that overcomes the problems associated with a telecommunications subscriber having to keep track of two different numbers and possibly having to dial two different numbers (a landline number and a wireless number) to reach a subscriber who utilizes both landline and wireless services.
Another object of the present invention is to provide a method and system that prevents the tromboning effect with respect to the routing of a call or other communication from a first device to a second device.
Another object of the present invention is to provide a method and system that prevents the tromboning effect with respect to the routing of a call or other communication between two communication networks wherein a call or other communication originates with a first network, is routed to a second network, and then is re-routed for termination or connection to a device operating in the first network.
Other objects, features, and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the drawings and the appended claims.